换句话说，如果按照这个比例制作一个半径30厘米的地球仪，那么它的赤道半径和极半径仅相差1毫米！
In other words, if according to the proportion of production with a radius of 30 cm of the globe, so its equatorial radius and the polar radius is only a difference of 1 mm!
如果你以北极点为中心开始画圆，那么半径和半个子午线相等的圆周就是赤道，它包含的区域就是北半球。
If you start from that North Pole as centre, then the circle with radius equal to a half meridian is the equator, and the area included is the northern hemisphere.
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